The present invention relates generally to blister packaging and more particularly, to blister components for blister packaging formed from multilayer thermoplastic films where a low moisture vapor transmission rate is desired.
Blister packaging is employed widely for commercial packaging of food products, personal care products, and human health products such as pharmaceuticals, and medical devices or precision instruments. The use of this type of packaging has become widespread mainly due to the ability in incorporate suitable moisture, dust, UV and/or gas barriers into the packages when such properties are desired for maintaining the product contained therein. For example, blister packaging is extensively used in the pharmaceutical industry for packaging of medicaments or the like in capsule, lozenge, or pill form because the integrity of the medicament can be maintained through the proper selection of materials used to form the packages.
For preparing blister packages or so-called push through packages, generally a thermoplastic film is first processed by vacuum forming or pneumatic forming so as to form blisters or cavities thereon, namely portions having a predetermined contour corresponding to each specific article to be received therein. After the so-blistered film has been solidified, each blister is charged with each piece of the article to be packaged and a second or lidding film is then covered over each blister and sealed to the first film. The second lidding film is often a laminate material which can be ruptured by a simple finger-rupture or peeled off from the first film to allow access to a packaged item. Conventional materials used for forming the blistered film have included transparent plastics such as polyvinylchloride (PVC), polyvinylidene chloride (PVdC) and polychlorotrifluoroethylene (PCTFE), commonly referred to as ACLAR® (Honeywell/Allied Signal). Packaging for pharmaceuticals or other moisture-sensitive articles require not only low moisture permeability but also other properties such as chemical inertness, clarity, rigidity, or uniform thickness. The use of polyvinylchloride (PVC) and polyvinylidene chloride (PVdC) have been shown to have poor and/or insufficient moisture-proofing properties required by the pharmaceutical industry. While ACLAR® exhibits relatively low moisture vapor transmission, its use in blister packaging is inherently costly.
There is therefore a need in the art for improved blister packaging materials which provides sufficient moisture vapor barrier and chemical inertness properties and is aesthetically pleasing enough to present the products contained therein while being cost effective to be manufactured.